Knauf 100mm OmniFit Thermal & Sound Glass Mineral Wool Insulation Slab 1200x400mm Pack of 6 (2.88m²)

Knauf 100mm OmniFit Thermal & Sound Glass Mineral Wool Insulation Slab 1200x400mm Pack of 6 (2.88m²)

Knauf 100mm OmniFit Thermal & Sound Slab is a versatile glass mineral wool insulation product designed to provide both thermal and acoustic performance across a wide range of wall, floor and pitched roof applications. It is suitable for timber and metal stud partitions, timber frame walls, timber floors and pitched roofs insulated at rafter level.

Each pack contains 6 slabs measuring 1200x400x100mm and provides approximately 2.88m² of coverage. The 100mm slab has a declared thermal conductivity of 0.035 W/mK, thermal resistance of 2.85m²K/W and Euroclass A1 reaction-to-fire classification, meaning it is non-combustible.

OmniFit Thermal & Sound Slab also achieves the best possible Sound Absorption Class A. At 100mm thickness it has a weighted sound absorption coefficient of αw 1.00 and is Quiet Mark certified, making it a strong choice where both thermal insulation and acoustic comfort are important.

Key Features & Benefits of Knauf 100mm OmniFit Thermal & Sound Glass Mineral Wool Insulation Slab:

• Manufacturer: Knauf Insulation


• Range: OmniFit® Thermal & Sound Slab


• Material: Glass Mineral Wool


• Thickness: 100mm


• Slab size: 1200x400x100mm


• Pack quantity: 6 slabs


• Coverage: 2.88m² per pack


• Thermal conductivity: 0.035 W/mK


• Thermal resistance: 2.85m²K/W


• Reaction to fire: Euroclass A1 - non-combustible


• Sound absorption: Class A


• Weighted sound absorption coefficient: αw 1.00


• Acoustic certification: Quiet Mark certified


• Applications: Internal partitions, timber frame walls, timber floors and pitched roofs at rafter level


• Technology: ECOSE® Technology


• Manufacturer product code: 883301


• EAN / GTIN: 5056667880900


• Packs per pallet: 42


• Provides thermal and acoustic insulation performance in one product


• Flexible glass mineral wool helps fit closely around minor irregularities


• Suitable for a wide range of residential and commercial insulation applications

100mm Thermal & Acoustic Insulation

Knauf OmniFit Thermal & Sound Slab is designed for building applications where both thermal efficiency and acoustic performance are required.

The glass mineral wool structure helps reduce heat transfer while also absorbing sound energy within wall, floor and roof cavities. At 100mm thick, the slab provides significantly greater thermal resistance than the 50mm version while retaining excellent acoustic absorption properties.

Where Can Knauf 100mm OmniFit Thermal & Sound Slab Be Used?

Knauf specifies OmniFit Thermal & Sound Slab for the thermal and acoustic insulation of a variety of constructions including:

• Timber stud partitions


• Metal stud partitions


• Timber frame walls


• Internal floors


• Separating floors


• Suspended timber ground floors


• Timber floors


• Pitched roofs insulated between rafters

The required insulation thickness and complete construction build-up should always be selected according to the individual project specification and applicable Building Regulations requirements.

Ideal for Internal Walls & Stud Partitions

The 100mm OmniFit slab is particularly suitable for deeper timber or metal stud partitions where both thermal performance and sound absorption are required.

The flexible glass mineral wool fits closely between suitable framing members, helping minimise gaps that could otherwise reduce the real-world thermal and acoustic performance of the completed wall.

Final acoustic performance depends on the complete wall construction, including framing, plasterboard specification, fixings and installation quality.

Sound Absorption Class A

Knauf OmniFit Thermal & Sound Slab achieves the best possible Sound Absorption Class A.

At 100mm thickness, the slab has a weighted sound absorption coefficient of αw 1.00, compared with αw 0.90 for the 50mm product.

This excellent sound absorption performance makes it suitable for bedrooms, home offices, living areas, internal partitions and separating floor applications where acoustic comfort forms part of the building design.

Quiet Mark Certified

OmniFit Thermal & Sound Slab has been awarded Quiet Mark certification.

Quiet Mark is an independent certification programme associated with the UK Noise Abatement Society charitable foundation and recognises products that make a contribution to protection from unwanted noise.

Independent Acoustic Performance

Knauf states that independent testing shows OmniFit Thermal & Sound Slab achieves the same or superior noise protection as traditional 45kg/m³ low-density rock mineral wool sound slabs.

This allows customers to achieve excellent sound absorption while benefiting from the flexible handling characteristics of glass mineral wool.

0.035 W/mK Thermal Conductivity

Knauf OmniFit Thermal & Sound Slab has a declared thermal conductivity of 0.035 W/mK.

At 100mm thickness, this product provides a thermal resistance of 2.85m²K/W.

The overall U-value achieved by a wall, floor or roof will depend on the complete construction build-up and not the insulation slab alone.

Euroclass A1 Non-Combustible Insulation

Knauf OmniFit Thermal & Sound Slab achieves a Euroclass A1 reaction-to-fire classification.

A1 is the best possible Euroclass reaction-to-fire classification and means the glass mineral wool insulation is classified as non-combustible.

Suitable for Timber Floors

OmniFit Thermal & Sound Slab is suitable for a range of timber floor applications, including internal floors, separating floors and suspended timber ground floors where specified.

Its acoustic absorption properties can help contribute to the sound performance of a correctly designed floor construction, while the 100mm thickness also provides useful thermal resistance.

Pitched Roof Insulation at Rafter Level

Knauf specifies OmniFit Thermal & Sound Slab for use between rafters in suitable pitched roof constructions.

The flexible slab can fit closely between suitable timber rafters, but the required total insulation build-up will depend on the roof design, rafter depth, ventilation strategy and thermal performance required by the project.

Flexible Glass Mineral Wool for a Close Fit

Glass mineral wool can adapt to minor imperfections within the surrounding structure and fit closely around framing members.

This helps reduce unintended air gaps in the insulation layer, supporting both thermal and acoustic performance.

Insulation should be fitted accurately without unnecessary gaps or excessive compression.

Pack of 6 - 2.88m² Coverage

Each pack contains 6 individual insulation slabs, with each slab measuring 1200x400x100mm.

The complete pack provides approximately 2.88m² of coverage.

When calculating the number of packs required, allow for the actual wall, floor or roof area together with framing, openings, cuts and appropriate installation wastage.

ECOSE® Technology

Knauf OmniFit Thermal & Sound Slab is manufactured using ECOSE® Technology, Knauf Insulation's plant-based binder technology.

This technology is used across Knauf's glass mineral wool insulation range and gives the insulation its distinctive natural brown appearance.

Standards & Certification

OmniFit Thermal & Sound Slab has a product declaration made in conformity with BS EN 13162:2012+A1:2015 for factory-made mineral wool insulation products.

The OmniFit product set also holds a CCPI Assessment Mark, certificate number 000600200/0228.

Knauf OmniFit Technical Datasheet

For full manufacturer technical information, performance data, acoustic performance, applications, certification and installation guidance, please refer to the official Knauf Insulation technical datasheet:

View Knauf OmniFit Thermal & Sound Slab Technical Datasheet

Installation Considerations

Install the slabs closely between suitable framing members without leaving unnecessary gaps and without excessively compressing the mineral wool.

Electrical cables, pipework, ventilation requirements, membranes and other building services should be considered before installation.

Always follow Knauf Insulation's current installation instructions and the specification for the complete wall, floor or roof construction.

Handling Glass Mineral Wool Insulation

Suitable personal protective equipment should be used when handling and cutting mineral wool insulation. Wear appropriate gloves, eye protection and respiratory protection where required.

A suitable sharp insulation knife or utility knife and straight edge can be used where slabs need trimming to fit around framing or building services.

Why Choose Knauf 100mm OmniFit Thermal & Sound Slab?

Knauf 100mm OmniFit Thermal & Sound Slab provides excellent thermal and acoustic performance in a versatile glass mineral wool slab. Its combination of 0.035 W/mK thermal conductivity, 2.85m²K/W thermal resistance, Sound Absorption Class A, αw 1.00 acoustic performance, Quiet Mark certification and Euroclass A1 non-combustible fire classification makes it suitable for a wide range of wall, floor and pitched roof applications.

With 6 convenient 1200x400x100mm slabs providing 2.88m² coverage per pack, it is particularly suitable for deeper partitions, timber floors, timber frame walls and pitched roof constructions where both thermal efficiency and acoustic comfort are required.